W126 differential reseal/refill - illustrated

[Thomaspin]

Thanks to Dave Morrison (dmorrison) for giving me the pointers on how to fix my leaking differential. I have a nice driveway and would like to keep it looking that way.

I have illustrated the job on my web site.

Go to Cars - Technical - Transmission.

Enjoy!

[jay3000]

I can't find a Transmission section.. I looked pretty hard too..

[Thomaspin]

http://www.pindelski.com/cars/W126/W126_differential_reseal_refill/W126_differential_reseal_refill.html

[GregS]

Does anyone know what size hex socket I need for a w124? I went through a lot of trouble to get a 14mm socket for my w123, and after reading Thomaspin's page, I'm afraid I might have to get another special tool.

GregS
'84 300D, 174k
'90 300CE, 163k

[dmorrison]

Great phototechnomanual.

For those who don't want to spend big $$$ on a 17MM allen tool consider this. The attached picture is the "tool" I used to remove and replace the Fuel tank screen on the 300TD. Now the screen does not require the torque that the differential does but it may work fine.
The bolt head is 22 MM. Put on 2 nuts. Jamb them and you have a "what ever size" MM allen wrench. Buy the metric bolt with a head that will do the job. We have a great "Hardware" store in DFW area, Elliots, that has all sorts of metric and SAE nuts and bolts. If you have a welder you could just spot weld the nuts on the bolt.

Total cost for my 22MM allen tool was 75 cents

And Yes Thomaspin, you do have a great driveway. The Pavestone makes a great driveway and walkway.

Dave

[dmorrison]

For those who want to do the Job that Thomaspin has described, on a 300TD wagon I have some advise.
I just replaced the differential mount on the 300TD
Due to the rear fuel tank in the wagon being behind the rear suspension. It is in the way of the 2 large bolts. I could not use a ratchet and socket to get to the 2 bolts. What I used was a 22MM socket and a 1 1/4 inch long piece of 3/8 square steel. The square steel is inserted into the socket and then a 3/8 open box wrench is used to turn the socket. Because of the setup you cannot torque the 2 large bolts.

All of this could be avoided if you remove the fuel tank. Not something I wanted to do, even though its empty. I estimated the torque on the 2 bolts and of course used loctite.
Keep the 2 bolts loose untill you have the 4 top mounting bolts torqued. You have to pry the unit around to get the bolts into the holes. Then you can "torque" the 2 bolts.

Additionally IF you lower the differential to assist in the access to the bolts. Make sure you disconnect the brake hoses and the sway bay connectors.

The picture shows the socket, the square tool and a C shaped tool I made for installing the subframe bushings.

Dave